Guide
How the kit works
Start with EX Special Attack: Thunder Shield Rush - High Voltage (Special) when Seth has enough Energy. It gives him 75% Resolve, deals Electric DMG and grants him a shield through Core Passive: Protector. You can hold the attack to charge it. Seth takes 40% less damage while charging and is invulnerable during the consecutive slashes.
At 75% Resolve or more, hold Basic Attack: Lightning Strike - Electrified. It spends 75% Resolve, and its Finishing Move triggers the Quick Assist of the squad member positioned before Seth when it hits. Core Passive: Protector grants that entering teammate a shield. Each shield is worth 80% of Seth's initial ATK, up to 3,000 points, and lasts 25 seconds. The self-shield and teammate-shield effects can each trigger once every 10 seconds.
Defensive Assist: Thundershield is another way to bring Seth in: it parries, deals Daze and gives him 25% Resolve. Follow it with Assist Follow-Up: Public Security Ruling to trigger the preceding teammate's Quick Assist on hit and pass them a shield. You can also hold after the follow-up to charge the EX Special Attack faster.
Chain Attack: Final Judgment and Ultimate: Justice Prevails each give 75% Resolve. The Ultimate also grants 3 Assist Points. If another squad member shares Seth's Attribute or Faction, Additional Ability: High Spirit makes his Chain Attack or Electrified Basic Attack's Finishing Move reduce the target's Anomaly Buildup RES for all Attributes by 20% for 20 seconds.
Build and why
Four pieces of Astral Voice are a strong option for Seth's Quick Assist handoffs. Whenever any squad member enters through Quick Assist, the set gains a stack, up to three. Each stack increases the entering character's DMG by 8% for 15 seconds. Its two-piece bonus also gives Seth 10% ATK.
Four pieces of Proto Punk are another good fit: a Defensive Assist or Evasive Assist from any squad member raises the whole team's DMG by 15% for 10 seconds. Its two-piece bonus increases Shield effect by 15%. Bunny in Wonderland is another four-piece option: Seth's EX Special Attack or a squad member's Defensive Assist or Evasive Assist adds a 6% team DMG stack, up to three, lasting 25 seconds.
For the remaining two slots, use Proto Punk for Shield effect or Hormone Punk for 10% ATK. Choose Percent ATK on discs 4 and 5, then Energy Regen or Percent ATK on disc 6. Look for Percent ATK first and Anomaly Proficiency second in substats. ATK supports the shield's initial ATK scaling, while Energy Regen helps Seth access his EX Special Attack.
Peacekeeper - Specialized is the first weapon choice. While Seth is shielded, it gives him 0.4 Energy Regen per second, and it raises Anomaly Buildup from his EX Special Attacks and Assist Follow-Ups by 36%. Spring Embrace is an alternative that reduces damage taken and transfers its Energy Generation Rate buff to the next on-field character. Bunny Band is another option, giving Seth 10% ATK while shielded.
Leveling priority
Level Core Passive: Protector first because it provides the shield and Anomaly Proficiency that make Seth useful to an Anomaly teammate. Follow with Quick Assist: Armed Support, then Basic Attack: Lightning Strike, Special Attack: Thunder Shield Rush, Chain Attack: Final Judgment and Dodge: Evasion Maneuver, in that order.
For maximum ascension, you need 800,000 Denny, 4 Basic Defense Certification Seal, 32 Advanced Defense Certification Seal and 30 Defender Certification Seal. For all skills, you need 2,905,000 Denny, 25 Basic Shock Chip, 75 Advanced Shock Chip, 250 Specialized Shock Chip, 5 Hamster Cage Pass, 9 Living Drive and 60 Higher Dimensional Data: Falling Fist.
Mindscapes worth it
Heroism (M1) is a useful support upgrade to consider. It increases both the shield value and its maximum limit by 30%, and the shield's Anomaly Proficiency bonus remains for 10 seconds after the shield ends.
Recklessness of Youth is another good option: Seth enters battle with 75% Resolve, and hits from his Electrified Basic Attack accumulate 35% more Electric Anomaly Buildup. Idealist (M6) is worth considering if you want more damage from Seth himself. Its extra Finishing Move damage equals 500% of his ATK, always crits and gains 60% CRIT DMG.
You can leave Core Aspiration for later if you mainly want shields and Anomaly support; it increases his Defensive Assist's Daze by 25%. Slow Reflexes and Distant Admiration add two levels to his main skill categories, but do not change how he passes the shield.
Teams
Put the teammate you want to shield immediately before Seth in the squad order, since his Finishing Move and Assist Follow-Up call that character through Quick Assist. An Anomaly character can make good use of the shield's Anomaly Proficiency bonus.
Common mistakes
Do not hold the Electrified Basic Attack before Seth has at least 75% Resolve. Use his EX Special Attack, Chain Attack or Ultimate to gain that amount, or build Resolve through Defensive Assists. Check the squad order before handing off, or the Quick Assist may bring in a different teammate than the one you wanted to shield.
Do not assume the teammate's shield refreshes on every handoff: its effect has a 10-second trigger interval. Also check the shared Attribute or Faction requirement before relying on the Anomaly Buildup RES reduction. Seth can still give shields without that Additional Ability active.
Do not ignore Seth's initial ATK when building for his shield. Anomaly Proficiency is useful, but the listed build puts Percent ATK ahead of it in substats. If you use a four-piece team buff set, remember that passive effects of the same name do not stack.
